Measuring the absolute decay probability of82Sr by ion implantation

We have developed a method of implanted ion counting in order to determine the absolute branching ratio of the 776.5 keV γ-ray transition in the decay sequence of 82Sr -> 82Rb -> 82Kr. A 215 MeV beam of 82Sr was produced at the Holifield Radioactive Ion Beam Facility and passed through an ionization chamber that counted and identified the ions before they were implanted into thin aluminum foils. Subsequent offline measurements using a Ge detector deduced the probability per decay of 82Rb for the 776.5 keV γ-ray in 82Kr to be 0.1493(38) in agreement with the accepted average value of 0.1508(16). This new technique measures directly the number of decaying nuclei in a given sample and significantly reduces the dependence on knowledge of the complete decay level scheme.